Rotary air lock



J. P. TAILOR ROTARY AIR LOCK" Oct. 6, 1964 2 Sheets-Sheet 1 Filed 001:.24, 1961 INVENTOR. JOHN P TmLoR J. P. TAILCR ROTARY AIR LOCK Oct. 6,1964 2 Sheets-Sheet 2 Filed Oct. 24, 1961 INVENTOR. JoHN P. TmLoR UnitedStates Patent 3,151,784 ROTARY AIR LOCK John P. Tailor, 415 Perry St.,Davenport, Iowa Filed Oct. 24, 1961, Ser. No. 147,275 Claims. (Cl.222368) This invention relates to a rotary feeder or air lock fortransferring particulate material of the granular and pulverulent type.

Rotary air looks or feeders have long been in use for discharging suchparticulate material from chambers (particularly where a pressuredifferential exists between the interior of the chamber and theexterior) and for feeding material to pneumatic conveyors. Such locksare subject to extreme wear, particularly where abrasive materials areinvolved. This has caused problems in the industry in maintainingeffective seals between pressured chambers or lines.

My invention compensates for wear as it occurs and thereby maintains aneffectively sealed rotary feeder, this compensation being accomplishedin a fashion which maintains the compensating elements in operativecondition over a long period of time by preventing the ingress ofmaterial into the compensating operating elements. A positive pressuredilferential is maintained around the operating elements which not onlyaids in biasing the elements into sealing engagement but also maintainsgas under pressure to insure an egress or outflow of gas therebypreventing an inflow of material.

Other important objects and advantageous features of my invention willbe apparent from the following description and accompanying drawingswherein for purposes of illustration herein specific embodiments of myinvention are set forth in detail and wherein:

FIG. 1 is a perspective view of a rotary air lock of the inventionutilized as a feeder for a pneumatic conveyor;

FIG. 2 is a cross-sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a perspective view of the rotor with a blade removed to showthe sealing strip; and

FIG. 5 is a perspective view of an alternate form of the rotor.

Referring to FIGS. 14, it will be seen that housing includes connectingflanges 36 and 37 and cylindrical inner wall 9 (FIG. 3) and transverseend walls 13 and 14. The housing includes an inlet 11 having an openingthrough the inner wall 9 and an outlet 12 having an opening through theinner wall 9 remote from the inlet opening; in the embodiment shown theinlet opening is directly below and diametrically opposed to the outletopening. The end walls 13 and 14 house bearings 15, 15 in which isjournaled a rotor 16, the rotor 16 including a central shaft 17 fromwhich outwardly extend longitudinal vanes 18 into sealing engagementwith the inner wall 9. The vanes 18 are equally spaced around the shaft17 and extend radially outwardly, the longitudinal ends thereofincluding wiper blades 28 slidably carried in longitudinal end slots 40.The rotor 16 also includes radial sockets 51 in the vanes 13 for housingblade resilient means or springs 36 which bias the blades 28 of therotor 16 into wiping sealing engagement with the inner wall 9 of housing10.

A fioating sealing end plate 19 circular in shape is mounted on the endportion of shaft 17 with its inner face in sealing contact with thetransverse ends of vanes 18 and blades 23 of rotor 16. It will be notedthat a floating sealing end plate is mounted on the other end portion ofshaft 17 in a manner similar to end plate 19. Both plates 19 and 20 aretransversely mounted ice between an end wall 13 and 14 respectively andits adiacent transverse end of the vanes 18.

The end plates 19 and 20 are longitudinally movable along shaft 17 butare held by presser pins 23 against rotational movement, each presserpin having lug 52 which locks in its respective socket 53 in the outersurface of its respective end plate 19 or 20. Each presser pin 23 alsohas a transverse face 54 which abuts the outer surface of its respectiveend plate 19 or 20 and transmits pressure from its spring 24 to its endplate to provide a sealing bias against the end plate. The springs 24and presser pins 23 are housed in end walls 13 and 14 in an annularpattern to insure equal force application to the end plates 19 and 20.

O-rings 22, 22 (FIG. 2) in the outer periphery of the circular endplates provide a seal with the inner wall 9 of housing 10. Similarly,U-shaped sealing strip 29 (FIG. 4) positioned in suitable grooves inblades 28 provide a seal with the side walls of the longitudinal slots46 in the vanes 18.

It will be noted in FIG. 2 that an annular portion of the inner wall 9of housing 10 provides the end boundaries of the inlet 11 and outlet 12along which the rubber or resilient wiper blades 28 slide as the rotor16 is rotated.

The shaft 17 is made up of a hollow intermediate section and solid endsections, the solid end sections having longitudinal gas passages 55, 55in fluid communication with the hollow intermediate section andextending longitudinally outwardly to transverse passageways 27, 27positioned inwardly of the bearings 15, 15. The end plates at this areaare cut away to form annular chambers 26, 26 around the shaft 17 influid communication with the transverse passageways 27 27. Gas undersuitable pressure (about 10 to 15 p.s.i.g.) is supplied to thesechambers 26, 26 through gas conduits 25, 25 in the end walls 13 and 14.To prevent gas escaping outwardly along the shaft to bearings 15, 15,seals 56, 56 are provided between the bearings 15, 15 and the chambers26, 26. Grease fittings 57 and 57 are provided for servicing thebearings.

Gas under pressure, therefore, is present in the annular chambers andthrough the structure described provides a gas means for maintaining gasunder pressure in the space between the outer surface of the end plates19 and 2t) and their respective end walls 13 and 14. This gas means alsoincludes means for maintaining gas under pressure in the longitudinalslot portion beneath or inwardly of the blades 28.

More specifically, gas flows from the annular chambers 26, 26 inwardlybetween the outer surface of shaft 17 and the surrounding portion of endwalls 13 and 14 to the transverse disc-like spaces 58, 58 between theend walls and the end plates. Gas in spaces 58, 58 passes into the rotorchamber of housing 10 when due to vibration or other cause the O-rings22, 22 temporarily fail to maintain a seal. In this fashion, foreignmatter and the granular or pulverulent material is kept out of thedisc-like spaces 58, 5S and the spring biased presser pins 23 are notfouled by such material. Shut-downs due to clogged presser pins anddisc-like spaces are thereby eliminated.

Similarly, the blade resilient means is continually protected fromclogging-thereby insuring a continuous sealing response of the rubberblades to wear and vibration. Gas passes from chambers 26, 26 throughtransverse passages 27, 27, longitudinal passages 55, 55, hollowintermediate shaft 17, and then through radial passages 31 in the vanes18 to the sealed bottom zone of longitudinal slots 40. The bottom zonesof longitudinal slots 40 are sealed by the rubber blades 28 and theU-shaped sealing strips 29, gas escaping from the longitudinal ends ofthe bottom zone of the slots being effectively sealed by engagement ofthe transverse ends of the blades with the sealing end plates.Similarly, gas escaping between the solid end shafts 17 and the annularwalls of the central holes in the end plates is prevented from flowinginto the rotor chamber in the housing 10.

The gas under pressure in the bottom zones of the longitudinal slots isavailable for blowing fine powder and the like out of the slots toinsure a free wear and vibration action of the blades.

The rotor shown in FIG. 4 is of welded construction, the vanes 18 beingwelded to the hollow intermediate shaft 17 with the solid end shaftsections welded thereto.

The rotor in FIG. 5 is of cast construction wherein the hollowintermediate shaft 17 and vanes 18 are cast in one piece and stub shafts32, 32 are bolted in central preferably baflles 34 and 35 are employedto direct the gas into the particulate material in a manner to insuresmooth flow. The rotary feeder may also be used to discharge materialsfrom bins and furnaces and the like.

It has been found that wear due to rubbing of the end plates on therotor is much less than that due to erosion and abrasion by theparticulate material being conveyed. V

In pneumatic conveyors, air is normally used but obviously for sensitivematerials, any inert gas may be employed.

While the present preferred embodiment of the invention has beenillustrated and described, it will be recognized that the invention maybe otherwise variously embodied and practiced within the scope of thefollowing claims.

What is claimed is:

1. A rotary feeder for particulate solids comprising a housing having acylindrical inner wall and transverse end walls forming a cylindricalchamber therein, said housing including aninlet having anopening'through said inner wall and an outlet having an opening throughsaid inner Wall remote from the other opening; a rotor mounted in saidhousing for rotation in said chamber, said rotor having a central shaftand longitudinal vanes extending outwardly therefrom into sealingengagement with said inner Wall, means for rotating said shaft, at leastone sealing end plate being transversely mounted between an end wall andsaid vanes and in substantially sealed relation with the inner wall atits periphery with provision for sliding longitudinal movement thereof,plate resilient means biasing said end plate longitudinally toward andinto complete sealing engagement with the end of the rotor, and gasmeans maintaining gas under pressure in the space between the outersurface of said sealing end plate and its adjacent end Wall to increasethe sealing bias and to insure an outflow of gas and thereby prevent aninflow of material.

2. A rotary feeder as defined in claim 1 and wherein the outer ends ofsaid longitudinal vanes include longitudinal slots, bladesmounted insaid slots, blade resilient means biasing said blades outwardly intosealing engagement with said inner wall, said gas means including meansfor maintaining gas under pressure in the slot portion inwardly of saidblade to insure an outflow of gas and to prevent an inflow of material.

3. A rotary feeder as defined in claim 2 and wherein sealing means areprovided between the blade and its slot to inhibit outflow of gastherebetween.

4. A rotary feeder as defined-in claim 3 and wherein said end wallsinclude bearings rotatably receiving the ends of said central shaft, anda sealing end plate is mounted on each end of the shaft adjacent saidvanes.

5. A rotary feeder for particulate solids comprising a housing having acylindrical inner wall and transverse end walls forming a cylindricalchamber therein, said housing including an inlet having an openingthrough said inner wall and an outlet having an opening through saidinner Wall remote from the other opening, said end walls havingbearings, a rotor having a central shaft with its ends journaled in saidbearings, means for rotating said shaft, said rotor having longitudinalvanes extending outwardly therefrom, the outer ends of said vanesincluding longitudinal slots, blades mounted in said slots, bladeresilient means biasing said blades outwardly of said slots into sealingengagement with said inner wall, sealing means between each blade andits slot, a sealing end plate mounted at each end of the central shaftwith its inner face in sealing contact with the ends of said vanesincluding said blades, plate resilient means for biasing said end platesinto sealing contact, and gas means including an annular gas chamber ineach of said end plates surrounding the shaft between each bearing andits end plate, first gas conduit means from said gas chamber to thespace between the outer surface of said sealing end plate and itsadjacent end wall to increase the sealing bias and to insure an outflowof gas and thereby prevent an inflow of material, and second gas conduitmeans from said gas chamber to the space in each vane slot inwardly ofsaid blade to increase the sealing bias and to insure an outflow of gasand thereby prevent an inflow of material.

References Cited in the file of this patent UNITED STATES PATENTS2,801,791 Walter Aug. 6, 1957 2,858,212 Durant et a1. Oct. 28, 19583,017,894 ChilCOat Jan. 23, 1962 FOREIGN PATENTS 803,857 Great BritainNov. 5, 1958

1. A ROTARY FEEDER FOR PARTICULATE SOLIDS COMPRISING A HOUSING HAVING ACYLINDRICAL INNER WALL AND TRANSVERSE END WALLS FORMING A CYLINDRICALCHAMBER THEREIN, SAID HOUSING INCLUDING AN INLET HAVING AN OPENINGTHROUGH SAID INNER WALL AND AN OUTLET HAVING AN OPENING THROUGH SAIDINNER WALL REMOTE FROM THE OTHER OPENING; A ROTOR MOUNTED IN SAIDHOUSING FOR ROTATION IN SAID CHAMBER, SAID ROTOR HAVING A CENTRAL SHAFTAND LONGITUDINAL VANES EXTENDING OUTWARDLY THEREFROM INTO SEALINGENGAGEMENT WITH SAID INNER WALL, MEANS FOR ROTATING SAID SHAFT, AT LEASTONE SEALING END PLATE BEING TRANSVERSELY MOUNTED BETWEEN AN END WALL ANDSAID VANES AND IN SUBSTANTIALLY SEALED RELATION WITH THE INNER WALL ATITS PERIPHERY WITH PROVISION FOR SLIDING LONGITUDINAL MOVEMENT THEREOF,PLATE RESILIENT MEANS BIASING SAID END PLATE LONGITUDINALLY TOWARD ANDINTO COMPLETE SEALING ENGAGEMENT WITH THE END OF THE ROTOR, AND GASMEANS MAINTAINING GAS UNDER PRESSURE IN THE SPACE BETWEEN THE OUTERSURFACE OF SAID SEALING END PLATE AND ITS ADJACENT END WALL TO INCREASETHE SEALING BIAS AND TO INSURE AN OUTFLOW OF GAS AND THEREBY PREVENT ANINFLOW OF MATERIAL.